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arXiv 2311.02166astro-ph.SR
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一颗正在活跃吸积的大陵五型食双星2M16212643+2136590的恒星属性

Stellar properties of an actively accreting Algol-type eclipsing binary 2M16212643+2136590

Marina Kounkel, Matteo Statti, Avani Kulkarni, Keivan G. Stassun, Meng Sun

AI总结:

本研究分析了含食双星2M16+21的分级三合星系统,发现其经历活跃质量转移,吸积星表面存在极小型高温热斑,供星或为亚亚巨星,可为双星演化及这类恒星形成研究提供参考。

摘要:

相互作用双星的演化过程与单星存在显著差异,因此需要更大规模的、恒星参数得到精确测定的此类系统样本,以理解这一过程的复杂性。我们对一个包含双线光谱食双星2M16+21的分级三合星系统开展了分析。计算结果表明,该系统已经历了显著的质量转移:目前供星的质量为0.33倍太阳质量(Msun)、半径为2.55倍太阳半径(Rsun),吸积星的质量为1.37 Msun、半径为2.20 Rsun,对应的质量比为4.2。尽管供星已经损失了超过初始气体总量一半的质量,质量转移过程仍处于活跃状态。吸积产生的激波在吸积星表面形成了一个温度约为光球层2倍的斑点,温度可达约10000 K,并产生显著的紫外超。该激波温度与处于活跃吸积阶段的主序前恒星中观测到的水平相当。这个仅约2度的致密热斑,是已观测到的存在双星质量转移的系统中尺寸最小的热斑之一,表明其形成时间较近,因此可用于明确追踪吸积流的撞击点。该系统的供星可能是亚亚巨星;将其与初始条件相似的系统进行对比,或有助于理解这类恒星的形成过程。

英文摘要:

Interacting binary stars undergo evolution that is significantly different from single stars, thus, a larger sample of such systems with precisely determined stellar parameters is needed to understand the complexities of this process. We present an analysis of a hierarchical triple containing a spectroscopically double-lined eclipsing binary, 2M16+21. Our calculations show that this system has undergone significant mass transfer, with the current mass and radius of the donor of 0.33 Msun and 2.55 Rsun, as well as the accretor of 1.37 Msun and 2.20 Rsun, resulting in a mass ratio of 4.2. Despite the already significant mass loss from the donor, shedding well over half its initial gas, mass transfer remains active. The shock from the accretion has produced a spot on the surface of the accretor that is ~2 times hotter than the photosphere, reaching temperatures of ~10,000 K and producing significant UV excess. This shock temperature is comparable to what is seen in the pre-main sequence stars that undergo active accretion. The compactness of the hot spot of just ~2 deg is one of the smallest observed in systems exhibiting binary mass transfer, pointing to the recency of its formation, as such it can be used to explicitly trace the point of impact of the accretion stream. The donor of this system may be a sub-sub-giant; comparing it with systems with similar initial conditions may help with understanding the formation processes of such stars.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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